The length of a rectangle is 2 times it's width if the perimeter of the rectangle is 36 inches find it's length and width

P = Perimeter

L = Length

W = Width

Perimeter of rectangle = L + L + W + W

or P = 2L + 2W

You know:

P = 36 inches

L = 2W [length is (=) 2 times it's width]

W = ?

P = 2L + 2W

Substitute/plug in what you know, plug in 2W for L since L = 2W

36 = 2 (2W) + 2W Simplify

36 = 4W + 2W

36 = 6W Divide 6 on both sides

6 = W Now that you know the width, you can find the length:

L = 2W

L = 2 (6)

L = 12

L = 12 in

W = 6 in

PROOF

P = 2 (12) + 2 (6)

P = 24 + 12

P = 36